Children enjoy various drawing and coloring activities using a variety of mediums. Useful in such activities are markers containing inks, crayons, pencils of various colors, and various paints including water colors, oil paints and acrylic paints. However, children would often like to change the color of a mark after they have made the mark. One instance would be the desire to add a yellow sun over a previously colored blue sky.
Coloring compositions generally are mixtures of a coloring matter dispersed or dissolved in a carrier fluid. The colorant, if readily dissolving in the carrier fluid, is termed a dye. An insoluble coloring material is termed a pigment. Pigments are finely ground solid materials and the nature and amount of pigment contained in an ink determines its color. Coloring composition may also optionally include such ingredients as humectants, preservatives, bittering agents, and drying agents. Humectants function to improve freeze/thaw stability and to control drying out of the tip when the coloring composition is used as a marker ink. Preservatives serve the obvious function of preventing spoilage of the ink during the expected shelf life of the marker product. Drying agents speed drying of a mark laid down by a marker. Bittering agents impart the coloring composition with an unpleasant taste, so that children and animals will not consume the coloring composition.
Changing the color of a mark is not readily done with the typical children's coloring instruments such as those described. In the past, children changed the marks by placing the mark of one color over the mark of another color. When performing this using traditional marking pens, the marks produced are often not the desired colors and the tips of the markers get soiled with the other inks, rendering the marker useless. If attempted with traditional children's paints, the colors tend to bleed together resulting in undesirable color smears. Therefore, there has been a long felt need for coloring compositions, including paints, inks, and markers containing such compositions, which produce marks of a first color that can be readily changed into a wide variety of second colors. Especially needed is such a group of compositions which may be used in markers without soiling the nib of the second used marking instrument.
In one available marker application, a child is able to change a specific initial mark laid down to a second specific color by applying a bleach to the first mark yielding a change in color. The marker inks used in these markers are typically prepared by blending a bleach or pH sensitive dye with a dye that is stable in bleach or high pH. For example, German Patent Specification No. 2724820, (hereinafter "the German Patent"), concerns the combining of a chemically stable dye and a chemically unstable dye in an ink formulation. Once a mark using this combination of stable and unstable dyes is laid down, the mark may be overwritten with a clear bleach solution, eliminating the color contribution of the unstable dye. The resulting mark of the stable dye, with its characteristic color, remains.
There are several drawbacks to such a marking system. First, there are strict limitations on the number of color changes which may be produced. Specifically, in formulations made according to the German Patent, the particular ink composition may only be changed from a first color to a fixed second color. For example, a green mark may only be changed to a violet color as the inks are described in the practice of the German Patent. In addition, since one of the required pair of markers contains only the bleaching agent, that bleaching marker cannot render a visible mark and may only be used in combination with the base color marker. Once the base color marker is used up, the bleaching marker is of no use. Or, once the bleaching marker is used up, the base color marker may only be used for the color which it initially marks with. A further disadvantage of the marking process of the German Patent is that the nib of the bleaching marker tends to get soiled by picking up the colors of the base coloring composition, thus tainting the color of subsequent marks.
Therefore, an object of the present invention is to provide a coloring composition system which is capable of enhanced multiple color changing abilities.
An additional object of the present invention is to produce a coloring composition system which includes at least two different coloring compositions each of which may be used independently or which may be used in combination to provide color changing ability.
A further object of the present invention is to provide a coloring composition system in the form of inks which prevents a nib of a color changing marker from becoming visibly soiled from contacting a base color composition.
These and other objects will become apparent to those skilled in the art to which the invention pertains.